Mendacity
by chipsandgravy523
Summary: Mendacity: a false appearance. People who hide their feelings, who run from their pasts, who are linked in ways no-one would believe. As NCIS and the FBI join forces on a case, they have no idea how much their lives are about to be changed by the existence of mendacity. Gabby & DiNozzo/OC! (Gorgeous banner by Nala @ TDA!)
1. The Morning After

**Author's Note: A quick thank you to my BFF Rosie (her username's DCIPHOENIX on this site if you want to check out some awesome NCIS stories) because she was the one who prodded me to get this posted :')**

**And just to let you guys know, I switch between places and times within the same chapter, so the words in bold are the places and dates that the segment is set in.**

**Now, onwards with Mendacity!**

**Chapter One: The Morning After**

* * *

_**Washington, D.C.**_

_**October 2012**_

It was a unseasonally brisk autumn morning as Special Agent Leroy Jethro Gibbs woke up on a ridiculously uncomfortable couch, cursing his hangover and the attached amnesia. It took him a few moments to deduce that the couch was in fact a coffin and that the aroma filling the air was coffee brewing, and he sat up with a groan, wondering where he was. He had the feeling he had done something ridiculously stupid the previous evening, but he couldn't recall the precise nature of said stupidity.

"Coffee for you, Gibbs." Abigail Sciuto chirped, setting a steaming mug in front of Gibbs. "I made it just the way you like it, so you can use it to sober up."

Gibbs nodded emphatically in agreement, instantaneously regretting it when the motion of his head worsened an headache he hadn't noticed he'd had, with all the worrying about the unidentified act of foolishness he had committed.

"I put some aspirin next to it too." Abby helpfully answered the Marine's unspoken question.

Gibbs quickly popped two pills out of the packet and put them in his mouth, then taking a large gulp of coffee before spluttering half of it out and swallowing the other half with a grimace. He quickly mopped up the spat-out coffee, muttering expletives under his breath, before looking up and seeing Abby staring at him with intense curiosity.

"What is this coffee, Abs?" he groaned.

"Oh. That must be the Irish coffee that Lacey left behind last time she stayed." Abby answered guiltily. "Sorry, Gibbs."

Gibbs opened his mouth to explain that whoever Lacey was, her taste in coffee was abysmal, but stopped himself at the sight of Abby's uncertain expression.

"Probably just drank too much in one go." he said instead. "Better to drink this in sips."

Abby nodded in agreement, and then there was silence. Gibbs started growing more uncomfortable, and he was sure that Abby noticed, but the pretty Goth sitting opposite him wasn't making any attempt to neutralize the growing tension.

"So... just how much did I embarrass myself last night?" he finally asked.

He was sure he could handle anything except admitting how he felt to Abby. While Gibbs knew that the younger woman would forgive him for a drunken mistake, the Marine didn't want his feelings to ruin his friendship with Abby, who he was absolutely sure saw him only as a father figure.

"You don't remember?" Abby asked, looking surprised.

"Side-effect of too much alcohol." Gibbs admitted. "I'm getting old."

"You're not old." Abby answered quickly- much too quickly.

There was another pause before Gibbs broke the silence once more.

"So what did I do?"

"Huh?"

"What'd I do to embarrass myself?"

"You mean, apart from splutter the last of my best friend's favourite coffee all over my brand new coffee table?" Abby raised an eyebrow, a cheeky expression written all over her face as Gibbs groaned.

It was hours later before Gibbs realized that he had underestimated his beautiful young forensic scientist; that Abigail Sciuto had skilfully managed to avoid answering his question.

* * *

_**Quantico, Virginia**_

_**October 2012**_

"WHITTIER!"

After realizing that the forensic scientist whose name he was shouting at the top of his voice was unable to hear him because of the Skullcandy headphones over her ears, FBI Agent Ron Sacks walked into the laboratory and slammed his hand onto the table in front of her.

"I heard you, Agent Sacks," she answered without looking up, one hand reaching up to pull down her headphones causing music to fill the room, "but last time I checked, it was considered polite to say good afternoon. You know, there's no harm in a 'Hello, Lacey' or even bringing me a coffee."

"What, like Fornell does?" Sacks asked, raising an eyebrow.

"Why else do you think Fornell gets his results faster than anyone else?" Lacey answered, bagging up her processed evidence.

Sacks surveyed the FBI's dark-haired, pale-skinned forensic scientist carefully, trying to work out if the question was rhetorical or not. Lacey looked up at him, her sapphire blue eyes filled with curiosity.

"I've just realized. You don't have any evidence that needs processing." she stated matter-of-factly.

"Correct." Sacks nodded. "I've come to deliver a message."

"I'm listening."

"One of Fornell's cases overlapped with one of NCIS' cases, so it's a joint case now. The Director wants one of the Bureau's forensic scientists to help out Abby Sciuto at NCIS, and since you're Fornell's favourite, he picked you." Sacks smirked as Lacey's nonchalant expression suddenly turned to one of concern as the blood drained from her face.

"But there's got to be some kind of conflict of interest?" she suggested, trying to think of a valid excuse why she couldn't go to the Navy Yard.

"There's nothing official linking you two." Sacks explained. "So there's no reason why you can't work at NCIS."

He leaned over to whisper into Lacey's ear; his voice barely audible, but loud enough for the words to send a chill down her spine.

"Tell Daddy dearest that I said hi."

* * *

**Please review; I'd love to hear what you think! This is my first fanfiction in a long time, so I'd love to hear suggestions on improvements!**

**And I have a question for you: who do you think is Lacey's father?**

**Whoever gets it right gets cookies ;)**


	2. The Night Before

**Author's Note: The normal text signifies scenes in the present; the text in italics are the flashbacks of the previous night.**

**Chapter Two: The Night Before**

* * *

_**Washington, D.C.**_

_**October 2012**_

Walking through the bullpen as he returned from his lunch, dropping his empty coffee cup in the bin and answering the phone just as it began to ring at the very moment he slid into his seat, Special Agent Leroy Jethro Gibbs went through the motions with apparent ease and speed, emitting secure confidence that he knew what he was doing; that he was calm and collected and his heart wasn't beating ridiculously fast.

_Gibbs was intently whittling wood, crafting a gift for Abby, who wanted a personalized gift ready in time for Christmas. He looked so good concentrating that Abby couldn't take her eyes off the older man. All she could think about was how much she wanted the Marine's callused hands on her and not the wood or his tools. Abby wondered once again why the handsome man she adored had insisted on working at her apartment and not his house, but Gibbs had refused to supply her with an answer._

"Jethro," the familiar voice of his old friend Ducky Mallard's voice reached his ears, "why on earth are you asking me to investigate the autopsy in a FBI cold case?"

"Because there's something there that seems odd. And before you say I should ask their ME, this isn't work, it's personal." Gibbs answered. "Please, Duck. Do this for me."

"If you thought that Dr. Kirkland missed something, why didn't you mention it at the time, Jethro?" Ducky chided gently, as if Gibbs was a child. "Didn't your famous gut tell you something was wrong?"

"It did, Duck."

"Then why did you wait four years before raising your suspicions?"

Ducky sounded slightly annoyed now, and Gibbs couldn't blame him. Whenever he thought back to that fateful night four years ago, he still remembered the terror on the sixteen-year-old's face. The striking sapphire eyes that captivated the attention of the people who met her, the gentle smattering of freckles across her nose and upper cheeks, the vivid jet-black hair. He remembered the excited phone conversation he'd had with her that evening, he remembered his fears that she was too young to get married, he remembered the handsome young man she loved and the gentle boy he had been. He remembered the phone call that changed his life, he remembered the FBI agent that saved hers, he remembered how that agent still fought for justice despite sacrificing so much. But what he hated was that four years on, he could not remember why.

_Almost as if he knew he was being surveyed, the silver-haired fox- she had certainly been on the money with that description- spoke with even looking up._

_"Is there something wrong, Abs?"_

_"No, Gibbs." Abby answered. "I'm just really impressed at how well you're doing that. I know you'll say it comes from practice, but I don't think I could ever make something that good even with a hundred years of practice."_

_"You saying I'm over a hundred years old?" the Marine laughed._

_"I'm saying you're naturally talented." the Goth answered._

_"You wanna tell me something I don't know?"_

_For a moment Abby felt compelled to tell Gibbs the truth; to confess the feelings that had been bubbling in her since he had returned from his retirement. At first she had managed to deny her attraction to the still-grieving man by continuing to keep up their façade of a father-daughter relationship. Whenever she had a new boyfriend, they complained she seemed distant and accused her of cheating on them, yet she had indulged them all in failed attempts to get over Gibbs._

"Boss?" Tony interrupted Gibbs' train of thought. "Do we have a lead?"

"No, DiNozzo." Gibbs answered, seeing the flicker of hope in Tony's eyes to fade. "You're still going through that paperwork; there might be something important hidden."

"Jethro," Ducky sighed, "I'm still on the phone."

"Then get off it and review that autopsy." Gibbs replied sharply before slamming the phone down. When he noticed his team looking at him warily, he barked. "What?"

"I have never known you to speak to Ducky in that way, and I have been part of this team for seven years." Ziva answered. "Is there a problem, Gibbs?"

"Why should there be a problem, Ziva?" Gibbs asked, getting up. "I'm going out to get coffee."

He got up and ignored his team's stares as he walked out of the bullpen, fighting his internal feelings. He knew if his closest friend Tobias Fornell knew about his predicament, he'd shout at him until his voice ran hoarse, then pester the Marine endlessly in "an attempt to knock some sense into that brain".

_"Abs?" Gibbs' voice snapped Abby out of her reverie. "Anything special going on in that head of yours?" _

_"Not really." Abby lied. "I'm gonna go to bed or I'll never wake up tomorrow."_

_The forensic scientist stood up, and instantly the alcohol she had drunk during the course of the night went straight to her head, causing her to stumble off-balance. Within what seemed like seconds, Gibbs had jumped from his seat and caught Abby gently._

But in Gibbs' world, it was different. And as far as he knew, Fornell had never been in this position. In fact, he'd probably babble on about how time changed people. Gibbs didn't want that to happen, though. As far as he was concerned, he was Leroy Jethro Gibbs, Marine and NCIS agent, one of the best at wooing women and one of the worst at keeping them, married four times and divorced three, and most importantly of all: up until now, he had been a father figure to Abby. He didn't ever want that aspect of his personality to ever change. He didn't want to be falling for Abigail Sciuto, who he was absolutely sure would regret her actions of the previous night should she recall them, when the said object of his affections was much, much younger than Gibbs. And as he finally noticed the fifteenth coffee shop he'd walked past, he heard Fornell's voice as clear as day in his mind.

"If your feelings are so precarious, Jethro, so questionable... couldn't Abby's be too?"

_It might have been the unusual close proximity of the two friends, it might have been the alcohol they had both consumed, it might have been that the smell of sawdust mixed with Gibbs' unique scent had gone to Abby's head. But for some unidentified reason, the younger woman tilted her head and kissed Gibbs. Not just a brushing of the lips, easily explained away, but a passionate kiss. It only lasted a few seconds before Gibbs pushed her off and clung to her shoulders while he spoke. _

_"You're drunk, Abby. You don't know what you're doing. Go to bed."_

_Abby had complied; had walked up the steps and fell onto her comfortable bed, pulling her duvet over her. And it was in true Abigail Sciuto fashion that she only realized something apocalyptically important in the moment before she fell asleep: that in those precious few seconds, Gibbs had responded to the kiss._

And that, he had absolutely no answer for.

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**Thank you everybody for your reviews! I was really interested to hear everyone's theories about who Lacey's father is; keep them coming! You'll find out who "daddy dearest" is in chapter three ;) I will say one thing though: she isn't Kelly.**

**I'd love to hear what you think of this chapter! I tried to keep it equal by having Gibbs' thoughts in the present tense and Abby's in the flashbacks so we know what both sides are thinking :)**

**I think I'm going to keep up asking you questions each chapter, it's awesome hearing your thoughts on Mendacity!**

**And today's question is: what would you like to see happen next with Gibbs and Abby? How does their romance develop? ;)**


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